Synergistic induction and turbocharging in internal combustion engine systems

ABSTRACT

Synergistic induction and turbocharging includes the use of one or more throttles in close proximity to each cylinder intake valve to control air flow in each intake port delivering air to combustion cylinders in an internal combustion engine system. A turbocharger may also be affixed in close proximity to each cylinder exhaust valve to enable a synergistic combination of hyper-filling cylinders with combustion air and immediate harvesting of exhaust gas by adjacent turbochargers. In some implementations the turbochargers may be low-inertia turbochargers. The combination of individual throttles per intake port and a turbocharger in close proximity to each cylinder enables faster ramp-up of an engine in the early stages of acceleration. Various implementations thus provide improved fuel economy and improved engine performance in tandem, instead of one at the expense of the other.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/467,708, filed on Mar. 23, 2017, entitled “SYNERGISTIC INDUCTION ANDTURBOCHARGING IN INTERNAL COMBUSTION ENGINE SYSTEMS,” which is acontinuation of U.S. patent application Ser. No. 15/254,138, filed onSep. 1, 2016, now U.S. Pat. No. 9,638,095, issued May 2, 2017, entitled“SYNERGISTIC INDUCTION AND TURBOCHARGING IN INTERNAL COMBUSTION ENGINESYSTEMS,” both of which are incorporated herein by reference in theirentirety for all purposes.

TECHNICAL FIELD

The disclosure relates to internal combustion engines and the use ofturbochargers therewith.

TECHNICAL BACKGROUND

Changes in motor vehicle internal combustion engines to improve fueleconomy and/or to reduce carbon emissions have led to “undersizedengines”—the utilization of smaller engines in vehicles that are largerthan those smaller engines were originally intended to serve. Efforts toreduce friction, to reduce pumping work and to address other challengeshave yielded engines having fewer combustion cylinders and/or smallerdisplacements than predecessor engines. At low load, the throttle of atraditional engine is substantially closed, reducing engine cylinderpressure. In such a situation the engine has to work to draw combustionair into the cylinders, thus causing a pumping loss that reduces engineefficiency and lowers fuel economy. Friction reduction has been achievedby reducing the number of combustion cylinders in engines and/orreducing the engine's displacement, again resulting in reduced enginepower.

Turbochargers have been employed to improve engine torque, but haveintroduced a performance problem for drivers; turbocharged engines havesuffered from turbo lag during acceleration. These new configurationsthus naturally result in both lower power and poorer performance attip-in and slow speeds. In addition to the negative impacts onperformance, fewer cylinders and/or smaller displacements mean reducedengine power more generally. New ways have been sought to generateadditional power to compensate for these deficiencies. Some solutionshave utilized twin-scroll, dual-nozzle and variable-geometryturbochargers, which add complexity to an engine's operation and layout.

Some earlier engine systems have replaced conventional throttlebutterfly valves with intake-valve-controlled throttling that uses anelectrical, electromechanical and/or hydraulic mechanism to controlindividual intake valve lift for each cylinder to regulate combustionair flow into the cylinder. These systems use a stepper motor to controla secondary eccentric shaft fitted with a series of intermediate rockerarms, which in turn control the degree of valve lift. The throttlebutterfly valve is no longer used to control the cylinder's combustionair supply, though for safety reasons it is still fitted as an emergencyback-up. Thus these earlier systems have additional hardware theincreases the complexity of crankshaft operation. Moreover, because theintake valves are used as combustion air control valves, tremendousspring and frictional valve spring forces and operationalcharacteristics must be addressed and overcome with an intake valvethrottling operation. These heavy spring and frictional forces diminishthe responsiveness of these intake-valve-as-throttle systems.

OVERVIEW

Synergistic induction and turbocharging includes the use of one or morethrottles in close proximity to each cylinder intake valve to controlair flow in each intake port delivering air to combustion cylinders inan internal combustion engine system. A turbocharger may also be affixedin close proximity to each cylinder exhaust valve to enable asynergistic combination of hyper-filling cylinders with combustion airand immediate harvesting of exhaust gas by adjacent turbochargers. Insome implementations the turbochargers may be low-inertia turbochargers.The combination of individual throttles per intake port and aturbocharger in close proximity to each cylinder enables faster ramp-upof an engine in the early stages of acceleration. These implementationsand others described herein provide concomitant improvements in bothfuel economy and engine performance. Frequently, improvements to fueleconomy have imposed performance limitations and, similarly, improvedengine performance has come with fuel economy degradation. Morespecifically, synergistic induction and turbocharging further improvesfuel economy because “real time” torque is greater under accelerationconditions and provides various benefits, including (withoutlimitation): the use of lower numerical axle ratios, lower “K” factortorque converters, earlier (i.e., lower engine RPM) shift schedules, andmore time and operating modes with fuel delivery held to a 14.6 to 1 airfuel ratio.

In internal combustion engine systems utilizing cylinders having onlyone intake port, a throttle is affixed in close proximity to any intakevalve(s) to control air flow through the intake port. In someimplementations a turbocharger is affixed in close proximity to eachcylinder's exhaust valve(s). The combination in these implementations ofone throttle per intake port and one turbocharger per cylinder providerapid filling of the cylinder with combustion air when the engine ceasesidle operation and provides substantial improvement in turbochargerperformance, in some instances eliminating perceptible turbo lag. Insome implementations a standard turbocharging system can be used, whichstill provides improved ramp-up of the turbocharger.

In internal combustion engine systems utilizing cylinders having twoseparate intake ports for each cylinder, a throttle is affixed in closeproximity to each intake port's intake valve(s) to control air flowthrough each intake port. An individual turbocharger can be affixed inclose proximity to each cylinder's exhaust valve, in some cases usinglow-inertia turbochargers to further enhance turbocharger ramp-up. Thedual-port throttles in each cylinder's induction system can be operatedin unison (i.e., so that all throttles are either open or closed) or canbe operated in a bifurcated or other manner. In some implementationsbifurcated operation of the throttles can include opening only onethrottle per cylinder when idle mode operation of the engine systemceases and maintaining single port air flow until peak single-porttorque is reached, after which the second throttle in each cylinderintake can be opened to permit air flow through both intake ports athigher loads.

Close proximity of a cylinder's throttle mechanism to that cylinder'sintake valve system can be characterized by the throttle-to-intakevolume defined in an intake channel between any throttle(s) and theirrespective intake valve(s). The throttle-to-intake volume can be limitedto 80% or less of the cylinder displacement or to 60% or less of thecylinder displacement in some implementations. Moreover, close proximityof a turbocharger to its respective exhaust valve(s) can becharacterized by the exhaust-to-turbine volume defined in an exhaustchannel between any exhaust valve(s) and the turbocharger's turbineinlet.

In both single-port and dual-port implementations, equalizing ports canbe used to provide generally even distribution of combustion air duringidle mode operation of the engine system. These ports can be passagesinterconnecting and allowing air flow between intake valves of thecombustion cylinders and may, in some implementations, includeequalizing port valves to close the equalizing ports whenever the enginesystem is not operating in idle mode. Moreover, balancing valves can beused to allow sharing of exhaust gas between turbochargers. Thesebalancing ports can be passages interconnecting and allowing exhaust gasflow between exhaust valves of the combustion cylinders and may, in someimplementations, including balancing port valves to prevent exhaust gassharing.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with referenceto the following drawings. While several implementations are describedin connection with these drawings, the disclosure is not limited to theimplementations disclosed herein. On the contrary, the intent is tocover all alternatives, modifications, and equivalents.

FIG. 1 illustrates an internal combustion engine system.

FIG. 2A illustrates one or more internal combustion engine systemcombustion cylinder assemblies.

FIG. 2B illustrates one or more internal combustion engine systemcombustion cylinder assemblies.

FIG. 3 illustrates one or more internal combustion engine systemcombustion cylinder assemblies.

FIG. 4A illustrates an internal combustion engine system.

FIG. 4B illustrates an internal combustion engine system.

FIG. 4C illustrates an internal combustion engine system.

FIG. 4D illustrates an internal combustion engine system.

FIG. 5 illustrates an internal combustion engine system.

FIG. 6A illustrates an internal combustion engine system.

FIG. 6B illustrates an internal combustion engine system.

FIG. 7 illustrates an internal combustion engine system.

FIG. 8 illustrates a method of operation of an internal combustionengine system.

FIG. 9 illustrates a method of operation of an internal combustionengine system.

DETAILED DESCRIPTION

Implementations of synergistic induction and turbocharging in aninternal combustion engine system can eliminate perceptible turbo lagthrough the interactive operation of induction and turbochargingsystems. Synergistic induction and turbocharging includesimplementations in which a throttle mechanism is operationally affixedin close proximity to each combustion cylinder's intake valve systemthat is supplied with combustion air by an intake port, for example byoperationally mounting a throttle plate in an intake channel comprisingan intake runner and/or intake port. Where each combustion cylinder in agiven engine has multiple intake ports, each of which suppliescombustion air to an intake valve system, an individual throttle can bemounted to regulate air flow through each individual intake port, thethrottle affixed in close proximity to each intake port's intake valvesystem, thus resulting in multiple throttles per combustion cylinder insome implementations.

This type of induction system allows for combustion cylinder“hyper-filling” (that is, faster and higher charge density filling ofeach cylinder). When this hyper-filling induction system is combinedwith a turbocharging system, perceptible turbo lag in internalcombustion engine systems can be eliminated because such hyper-fillingcan immediately ramp up a turbocharging system (including turbochargingsystems comprising an individual turbocharger affixed in close proximityto each cylinder's exhaust valve(s)).

Some implementations further include an individual turbocharger having aturbine inlet affixed in close proximity to each combustion cylinder'sexhaust port. As explained in more detail herein, an individual throttleper intake port and an individual turbocharger each affixed in closeproximity to a single combustion cylinder provide substantially enhancedtip-in and ramp-up as compared to combustion cylinder configurationslacking one or both of the individual throttle and/or individualturbocharger per cylinder. In some implementations low-inertiaturbochargers can be implemented to further enhance tip-in and ramp-upof the engine system.

Faster induction filling, in addition to producing faster and highercharge cylinder filling, likewise leads to faster and higher energyfeeding of turbocharger turbine wheels, which synergistically producesmore rapid acceleration of the turbine wheel and compressor wheel tofurther enhance increased charge density and acceleration of the turbinerotational speed and compressor wheel speed. Induction system fill timeis reduced by operationally affixing an individual throttle to regulateair flow through each cylinder intake port in close proximity to thecylinder intake valve(s) associated with that intake port, thusdecreasing the volume of air between the throttle plate and the intakevalve. The volume to fill can be reduced by 90% when compared to anengine configuration in which an intake throttle is located at theintake manifold entrance. The total intake volume (that is, theaggregate volume of the plumbing, intake manifold, runners, etc. betweenan upstream intake manifold throttle and the cylinder intake valves isroughly equal to the engine displacement (that is, a 2.0 liter enginewould be expected to have 2.0 liters of induction volume). Affixation ofindividual throttles in close proximity to their associated intakevalve(s) can dramatically reduce this induction volume and thussubstantially improve cylinder induction speed and charge density. Whenthese induction system improvements synergistically interact withindividual turbochargers having turbine inlets affixed in closeproximity to cylinder exhaust valves, engine performance improvementsare realized. Such systems can reduce turbocharger turbine wheel inertiaand capture exhaust blow-down pulse energy, which many earlier systemshave failed to do. Implementation of low-inertia turbochargers furtherenhances this energy harvesting and compressed air generation function.

As noted above, some earlier systems have utilized turbochargers tocorrect for undersized engine torque and horsepower shortcomings.However, because turbochargers operate at very high RPM (e.g., 100,000to 200,000 RPM), drivers notice the period of time required to ramp upto such operating levels, commonly known as “turbo lag,” resulting insluggish vehicle performance during acceleration from a standing start.This sluggish performance is typically experienced between idle modeoperation (e.g., ˜600-900 RPM) up to ˜3,000 RPM during acceleration froma standing start. There are some fundamental problems responsible forthis sluggish performance that are addressed and eliminated byimplementations of synergistic induction and turbocharging herein: (1)significantly long intake manifold filling time from idle toacceleration due to intake manifold vacuum during and to help controlidle mode operation (acceleration requires converting vacuum toatmospheric positive pressure to begin engine torque rise) and the largevolume of the intake manifold and related plumbing; (2) peak enginetorque being delayed until high RPM operation (typically between 3,000and 4,400 RPM, which is well above where it is needed (between idle and˜3,000 RPM); and (3) delayed turbocharger boosting benefits due to thelong ramp up time from idle up to ˜150,000 RPM. Earlier systems thathave added turbochargers to compensate for small engine power shortfallscause delays and earlier systems have failed to recognize and utilizeinterdependent synergistic induction and turbocharging to overcome theengine power shortfall and concurrently avoid turbo lag (a vehicleoperator typically perceives turbo lag when the delay is more than 300milliseconds).

Implementations of synergistic induction and turbocharging describedherein provide concomitant improved fuel economy and enhanced engineperformance. Frequently, improvements to fuel economy have limitedand/or diminished engine performance and, similarly, enhancements toengine performance have degraded fuel economy. More specifically,synergistic induction and turbocharging improves fuel economy because“real time” torque is greater under acceleration conditions and providesvarious benefits, including (without limitation): the use of lowernumerical axle ratios, lower “K” factor torque converters, earlier(i.e., lower engine RPM) shift schedules, and more time and operatingmodes with fuel delivery held to a 14.6 to 1 air fuel ratio.

Poor acceleration response can be markedly improved by using anindividual throttle to regulate combustion air flow through each intakeport in the engine (e.g., using a single close-proximity throttle foreach cylinder where each cylinder has one intake port, and using asingle close-proximity throttle for each intake port where each cylinderuses two or more intake ports). A single throttle has traditionally beenlocated at the inlet of the engine induction system (typically upstreamof and near the inlet to an intake manifold), which results in long filltime when switching from idle vacuum to acceleration positive pressurecharging. Stated another way, in earlier engine systems in which asingle throttle is located at the intake manifold entrance, an inductionsystem vacuum is created when the throttle is closed, substantiallydropping pressure in the intake manifold and any intake runners andother downstream apparatus used to supply combustion air to thecylinders. When such a throttle is opened to begin acceleration, theinduction system's low-pressure (e.g., vacuum) volume between thethrottle and the combustion cylinder intake valves must be filled toprovide acceleration positive pressure charging (e.g., atmosphericpressure) to the intake valves. Moreover, implementations of synergisticinduction and turbocharging are more efficient, responsive and stablethan systems utilizing intake valves to throttle combustion air flowinto combustion cylinders. Moreover, implementations of synergisticinduction and turbocharging can remove perceptible turbo lag in internalcombustion engine systems.

Acceleration response in an engine includes the dynamics of threefunctional stages: (1) before combustion, (2) during combustion, and (3)after combustion. The stage before combustion is referred to as chargeloading, referring to the charge density at the intake valvesimmediately before they open. Ideally, the charge density wouldpreferably be equal to one bar, or 14.7 psi (i.e., atmosphericpressure). Lower pressures slow transient response (i.e., the time ittakes for the engine to respond to a change in throttle position).

As seen schematically in FIG. 1, an internal combustion engine system100 includes an induction system 110 providing combustion air to acombustion cylinder array system 140, which in turn discharges exhaustgas to drive a turbocharging system 180, which then delivers the exhaustgas to an exhaust system 190. In some implementations a portion of theexhaust gas can be used in an exhaust gas recirculation (EGR) system.One or more individual throttles are provided for each combustioncylinder in engine system 100 to regulate combustion air flow in eachcylinder intake port and to provide approximately atmospheric pressureat the upstream surface of the throttle plates, each of which isoperationally affixed in close proximity to each cylinder's intake valvesystem (which typically consists of either one intake valve or twointake valves). This substantially reduces or minimizes the inductionvolume between each throttle plate and its associated intake valvesystem so that implementations of synergistic induction andturbocharging dramatically reduce induction fill time and increasecharge density when compared with earlier induction systems and enginesystems. Moreover, in some implementations, this improved inductionperformance is combined synergistically with enhanced turbocharging,resulting in improved fuel economy (e.g., for passenger vehicles andlight trucks that have more frequently been outfitted with smallengines), improved engine performance (especially at tip-in), and themitigation or elimination of perceptible turbo lag.

In one or more implementations of synergistic induction andturbocharging illustrated in FIG. 1, several cylinders are housed withinand/or defined by a cylinder block and a cylinder head 102 that alsotypically defines a plurality of intake ports and exhaust ports for thecylinders. Each cylinder is configured to contain periodic combustion ofa mixture of fuel and combustion air (the charge). Moreover, eachcylinder has a cylinder displacement that is defined as the area of thecylinder bore times the piston stroke in the cylinder.

Three basic cylinder intake configurations (comprising intake ports andintake valves) will be used to assist in describing non-limiting,illustrative examples of synergistic induction and turbocharging. In afirst cylinder intake configuration (referred to as “IntakeConfiguration 1”), each combustion cylinder has a single intake portthat provides combustion air to an intake valve system having a singleintake valve that controls the admission of combustion air into thecylinder (one example of Intake Configuration 1 is shown in FIG. 2A,with intake port 231 supplying combustion air to cylinder 251 through asingle intake valve 241). In a second cylinder intake configuration(Intake Configuration 2), each combustion cylinder has a single intakeport but utilizes two intake valves in the intake valve system tocontrol combustion air flow into the cylinder (one example of IntakeConfiguration 2 also is shown in FIG. 2B, with intake port 231 supplyingcombustion air to cylinder 251 through two intake valves 241A and 241B).In the third illustrative configuration (Intake Configuration 3), eachcylinder has two intake ports, each of which supplies combustion air toa distinct intake valve system, each of which has a single intake valvecontrolling combustion air admission into the cylinder (i.e., two intakeports and two intake valves provide two distinct intake channels(combustion air supply paths)). An example of Intake Configuration 3 isshown in FIG. 3, with intake port 331A supplying combustion air tocylinder 351 through intake valve 341A and intake port 331B supplyingcombustion air to cylinder 351 through intake valve 341B. Therefore, inIntake Configurations 1 and 2, a single intake port supplies combustionair to an intake valve system that can have one or two intake valves,respectively. In Intake Configuration 3, each cylinder has two intakevalve systems, one for each intake port supplying combustion air to thecylinder. Engine systems in which these configurations and theirassociated implementations of synergistic induction and turbochargingcan be used include spark-ignited engines having two or more combustioncylinders.

Each cylinder also has an exhaust valve system that includes at leastone exhaust valve that controls the discharge of exhaust gas from thecylinder to an exhaust channel A cylinder's exhaust channel includes anexhaust port and any runner or other extension of the exhaust portpathway for exhaust gas. Similarly, a cylinder's intake channel includesan intake port that supplies combustion air to the cylinder intake valvesystem plus any runner(s) or other combustion air pathway connected tothe intake port for supplying combustion air to the cylinder.

In FIG. 1, combustion cylinder 151 has an intake valve system thatincludes one or more intake valves 141 connecting cylinder 151 to acombustion air source 118 via a combustion air intake channel (e.g.,intake runner(s) 111 and intake port(s) 131, where at least one intakeport 131 is defined inside cylinder head 102 and an intake runner 111 isexternal to the cylinder head 102). In some implementations the intakeports and exhaust ports of the combustion cylinders are defined by thecylinder head 102. A throttle mechanism for cylinder 151 includes one ormore throttles 121, each of which is operationally mounted to or withina runner 111 (or mounted to or within an intake port 131, or mounted atthe interface between an intake runner 111 and an intake port 131). Eachthrottle includes a throttle plate (or similar component) affixed inclose proximity to its associated intake valve system, such as intakevalve(s) 141 of cylinder 151's intake valve system. Each throttle plate(or similar component) can be fixed on a shaft that is rotatably mountedin the walls of an intake channel that can comprise an intake port,intake runner and/or other intake passage to control the flow of air bymovement between a closed throttle or engine idle mode position an openthrottle position.

Generally, implementations of synergistic induction and turbochargingutilize a throttle mechanism (comprising one or two throttle plates)affixed in close proximity to a cylinder's intake valve system(comprising one or two intake valves). Thus a throttle-to-intake volumecan be identified between each cylinder's throttle mechanism and itsintake valve system (i.e., the cylinder throttle mechanism is separatedfrom the intake valve system by the throttle-to-intake volume). Whereonly one intake port regulates combustion air flow to a cylinder (as inIntake Configurations 1 and 2, above), one throttle is used for thatcylinder, and the throttle-to-intake volume is defined as the volumeseparating that throttle from any intake valve(s) in that cylinder'sintake valve system (where the throttle and intake valve(s) are closed).Where two separate intake ports regulate combustion air flow to acylinder, two throttles are used for each cylinder (one throttleregulating air flow in each intake port), and that cylinder's totalthrottle-to-intake volume is defined as the sum of the volumes thatseparate the throttles from their respective intake valves (that is, thesum of each intake channel between its throttle and its associatedintake valve(s), as in Intake Configuration 3), again where thethrottles and intake valves are closed. It should be noted that incylinders with multiple intake ports, each intake channel'sthrottle-to-intake volume does not have to be equal to the other(s),meaning that throttle plates for the same cylinder's intake can beaffixed to define different volumes between the throttle plate and itsassociated intake valve system.

More specifically, when a cylinder has an intake valve system comprisinga single intake valve supplied with combustion air by a single intakeport (e.g., Intake Configuration 1 and/or as illustrated in thenon-limiting example of FIG. 2A), in some implementations a throttleplate affixed in close proximity to the intake valve system isoperationally mounted to control combustion air flow through the intakeport and so that the throttle-to-intake volume is less than or equal to80% of the cylinder's displacement, where the throttle-to-intake volumeis defined as the intake channel volume between the throttle plate andthe intake valve when both are closed (where the intake channel volumemay include intake port volume and intake runner volume, if any, betweenthe closed throttle plate and closed intake valve, not including anyequalizing port(s) volume).

When a cylinder has an intake valve system comprising a single intakevalve supplied with combustion air by a single intake port, in someimplementations a throttle plate affixed in close proximity to theintake valve system is operationally mounted to control combustion airflow through the intake port and so that the throttle-to-intake volumeis less than or equal to 60% of the cylinder's displacement.

When a cylinder has an intake valve system comprising a single intakevalve supplied with combustion air by a single intake port, in someimplementations a throttle plate affixed in close proximity to theintake valve system is operationally mounted to control combustion airflow through the intake port and so that the linear distance thecombustion air travels from the throttle plate to the cylinder intakevalve is less than or equal to 10 inches, 8 inches, 6 inches, 4 inchesor 2 inches.

When a cylinder has an intake valve system comprising multiple intakevalves supplied with combustion air by a single intake port (e.g.,Intake Configuration 2 and/or as illustrated in the non-limiting exampleof FIG. 2B), in some implementations a throttle plate affixed in closeproximity to the intake valve system is operationally mounted to controlcombustion air flow through the intake port and so that thethrottle-to-intake volume is less than or equal to 80% of the cylinder'sdisplacement, where the throttle-to-intake volume is defined as theintake channel volume defined between the throttle plate and the intakevalves when all are closed.

When a cylinder has an intake valve system comprising multiple intakevalves supplied with combustion air by a single intake port, in someimplementations a throttle plate affixed in close proximity to theintake valve system is operationally mounted to control combustion airflow through the intake port and so that the throttle-to-intake volumeis less than or equal to 60% of the cylinder's displacement.

When a cylinder has an intake valve system comprising multiple intakevalves supplied with combustion air by a single intake port, in someimplementations a throttle plate affixed in close proximity to theintake valve system is operationally mounted to control combustion airflow through the intake port and so that the linear distance thecombustion air travels from throttle plate to at least one of the intakevalves is less than or equal to 10 inches, 8 inches, 6 inches, 4 inchesor 2 inches.

When a cylinder has an intake valve system comprising a first intakevalve supplied with combustion air by a first intake port and a secondintake valve supplied with combustion air by a distinct second intakeport (e.g., Intake Configuration 3 and/or as illustrated in thenon-limiting example of FIG. 3), in some implementations first andsecond throttle plates are affixed in close proximity to the intakevalve system when the first throttle plate is operationally mounted tocontrol combustion air flow through the first intake port and the secondthrottle plate is operationally mounted to control combustion air flowthrough the second intake port and so that the throttle-to-intake volumeis less than or equal to 80% of the cylinder's displacement, where thethrottle-to-intake volume is defined as the sum of (a) the first intakechannel volume defined between the first throttle plate and the firstintake valve when both are closed plus (b) the second intake channelvolume defined between the second throttle plate and the second intakevalve when both are closed.

When a cylinder has an intake valve system comprising a first intakevalve supplied with combustion air by a first intake port and a secondintake valve supplied with combustion air by a distinct second intakeport, in some implementations first and second throttle plates areaffixed in close proximity to the intake valve system when the firstthrottle plate is operationally mounted to control combustion air flowthrough the first intake port and the second throttle plate isoperationally mounted to control combustion air flow through the secondintake port and so that the throttle-to-intake volume is less than orequal to 60% of the cylinder's displacement.

When a cylinder has an intake valve system comprising a first intakevalve supplied with combustion air by a first intake port and a secondintake valve supplied with combustion air by a distinct second intakeport, in some implementations first and second throttle plates areaffixed in close proximity to the intake valve system when the firstthrottle plate is operationally mounted to control combustion air flowthrough the first intake port and the second throttle plate isoperationally mounted to control combustion air flow through the secondintake port and so that the linear distance the combustion air travelsbetween each throttle plate and its associated intake valve is less thanor equal to 10 inches, 8 inches, 6 inches, 4 inches or 2 inches. Athrottle mechanism separated from a cylinder intake valve system by anintake manifold is not affixed in close proximity to that cylinderintake valve system.

Each throttle plate is operationally mounted to control combustion airflow through one of the intake ports. Thus, in intake valve systemshaving a single intake port servicing a single cylinder, there is asingle throttle controlling combustion air flow through that intake port(e.g., in Intake Configurations 1 and 2 described above). Where multipleintake ports independently supply combustion air to a cylinder (e.g., inIntake Configuration 3 described above), there is an individual throttlefor each such intake port. Throttle plates can be operated in unison ina given engine system, or they can be operated in a staged manner,grouping throttles into subsets that are operated independently in amanner that is appropriate for the desired performance characteristicsof the engine system.

Exhaust gas is discharged from combustion cylinder 151 via an exhaustvalve system that includes at least one exhaust valve 161 controllingthe discharge of exhaust gas to an exhaust channel (e.g., exhaust port171). The discharged exhaust gas powers a turbocharger 181 that has aturbine inlet affixed in close proximity to exhaust valve 161. In someimplementations a turbocharger turbine inlet affixed in close proximityto its associated exhaust valve is operationally mounted or otherwisesituated so that an exhaust-to-turbine volume is less than or equal to80% of the cylinder displacement, where the exhaust-to-turbine volume isdefined as the exhaust channel volume between a closed exhaust valve andthe turbocharger's turbine inlet (where the exhaust channel volumeincludes any exhaust port volume and exhaust runner volume, if any,between the closed exhaust valve and the turbocharger's turbine inlet,not including any balancing port(s) volume). In some implementations aturbocharger turbine inlet affixed in close proximity to a cylinderexhaust valve can be operationally mounted or otherwise situated so thatthe cylinder's exhaust-to-turbine volume is less than or equal to 60% ofthe cylinder displacement. In some implementations a turbochargerturbine inlet affixed in close proximity to its associated exhaust valveis operationally mounted or otherwise situated so that exhaust gasdischarged from a cylinder still possesses its pulse characteristics asit enters the turbocharger turbine inlet. In some implementations aturbocharger turbine inlet affixed in close proximity to its associatedexhaust valve is operationally mounted or otherwise situated so that thelinear distance the exhaust gas travels from exhaust valve to theturbocharger turbine inlet is less than or equal to 10 inches, 8 inches,6 inches, 4 inches or 2 inches. A turbocharger separated from a cylinderexhaust valve by an exhaust manifold is not affixed in close proximityto that cylinder exhaust valve.

Similar routing of combustion air and exhaust gas and spacing ofthrottle plates and turbochargers can be implemented with regard tocylinder 152 (using an intake channel having intake runner(s) 112 andintake port(s) 132, a throttle mechanism including one or more throttles122, an intake valve system having one or more intake valves 142,cylinder 152, at least one exhaust valve 162, an exhaust channelincluding at least one exhaust port 172, and turbocharger 182) and withregard to cylinder 153 (using an intake channel having intake runner(s)113 and intake port(s) 133, a throttle mechanism including one or morethrottles 123, an intake valve system having one or more intake valves143, cylinder 153, at least one exhaust valve 163, an exhaust channelincluding at least one exhaust port 173, and turbocharger 183). Again,as noted, implementations of synergistic induction and turbocharging canbe implemented in engine systems having 2 or more combustion cylindersand descriptions of and references to Figures having three cylinders arenon-limiting examples.

In some implementations a plurality of equalizing ports interconnect thecylinders' intake ports to generally uniformly distribute combustion airflow to the cylinder intake ports during idle mode operation of theengine system 100. These equalizing ports also help to accommodatediffering amounts of throttle leakage when the one or more throttles percylinder are closed, which could otherwise lead to unstable engine idlemode operation. Each equalizing port comprises a proportionally-sizedpassage (e.g., to provide the desired idle mode combustion air flow anddistribution, and/or to remove the effects of throttle leakage (whichtypically differ from throttle to throttle) when the throttles areclosed). Each equalizing port also can comprise an equalizing port valvethat controls air flow through its respective passage.

In FIG. 1 equalizing port 124 connects combustion cylinder 151's intakeport (e.g., having a connection point at intake runner 111 and/or intakeport 131) to combustion cylinder 152's intake port (e.g., having aconnection point at intake runner 112 and/or intake port 132).Equalizing port connections can be placed just downstream of theirrespective throttles 121 and 122 and upstream of respective intakevalves 141 and 142 of combustion cylinders 151 and 152, respectively.Equalizing port 124 can be an open passage or may utilize a valve 126 orother flow control device that can open and close port 124 to controlair flow through port 124. Pressure spikes, peaks, valleys, etc. (i.e.,differences in pressure between combustion cylinders) can disrupt orotherwise negatively affect air flow in the combustion cylinders.Therefore, equalizing ports can be employed during idle (where verysmall air flows provide conditions for more substantial pressure andflow differences that can destabilize idle operation) and during otheroperating conditions to assist in mitigating some pressure and/or flowdifferences. Under acceleration modes it is advantageous to harvest peakpressures during induction filling which will have a ramming effect,increasing charge density and subsequent engine output (e.g., by closingthe equalizing ports to prevent cross channel flow). Moreover, highervelocity filling provides more charge motion after the intake valve isclosed, which allows higher levels of EGR, thus lowering NOx emissionsand improving fuel economy.

Similarly, equalizing port 125 connects combustion cylinder 152's intakeport (e.g., having a connection point at intake runner 112 and/or intakeport 132) to combustion cylinder 153's intake port (e.g., having aconnection point at intake runner 113 and/or intake port 133) justdownstream of their respective throttles 122 and 123 and upstream of therespective intake valves 142 and 143 of combustion cylinders 152 and153, respectively. Equalizing port 125 also can be an open passage ormay have a valve 127 or other flow control device that can open andclose port 125 to control air flow through port 125. Each equalizingport 124, 125 acts as an idle mode air flow equalizing port that assistsin stabilizing combustion air flow to the combustion cylinders 151, 152,153 when engine system 100 is operating in idle mode and all of thethrottles 121, 122, 123 are closed. Such stabilizing combustion air flowduring idle mode operation allows for smoother engine operation. Ports124, 125 may be used in other engine operating conditions as well insome implementations.

In some implementations each throttle 121, 122, 123 can be defined by athrottle body or housing that includes operational mounting of athrottle plate just upstream of a connection point for one or more ofthe equalizing ports 124, 125. In other implementations the connectionpoints for equalization ports 124, 125 may be distinct from the throttlestructures.

One or more sensors 128 can be connected to the cylinder array (and/orother components of the engine system 100) to provide operational andother data to an engine control system 101 (e.g., an engine control unit(ECU) or the like). For example, combustion air temperature and pressurecan be measured and supplied to engine control system 101 to permitproper air-to-fuel ratios for optimal or desired combustioncharacteristics (e.g., charge density is dependent upon temperature anddensity of the combustion air used). Thus air pressure during idle modeoperation and/or in other operating conditions can be measured and thatdata utilized accordingly. In FIG. 1 engine control system 101 includesone or more processors 902, memory 903 and one or more interfaces 905.Engine control system 101 can also include circuitry such as thecircuitry used in an engine control unit (ECU) as well as collected andstored data and other aspects of engine mapping. As disclosed herein,various systems, apparatus, methods, etc. can be implemented inconnection with such an engine control system, for example, through dataprocessing and control logic that depends on one or more engine systemparameters and/or conditions. Sensors and the like can transmit data toengine control system 101 using interfaces and links, after which enginecontrol system 101 can generate control commands, signals and the liketo various engine system components (sensor and/or other types of datacan be collected and control signals deployed via communication lines907, non-limiting examples of which are shown in the Figures). As isknown to those skilled in the art an ECU or similar control system canbe configured to receive a variety of inputs (e.g., pressure,temperature, mass air flow, vehicle operator actions and inputs, enginespeed and/or load) and to control a variety of functions and components(e.g., throttle control system(s), turbochargers, valves, air flowcontrols, exhaust gas controls, wastegates).

An idle mode combustion air supply line 137 is connected to at least oneof the cylinders' combustion air intake channels (e.g., runner 113 orintake port 133) downstream of any throttle associated with that airintake channel (e.g., at the same connection point as equalizing port124 or 125). Combustion air flow through line 137 can be regulated orotherwise controlled by a throttle bypass valve 129 that selectivelyregulates the flow of combustion air (e.g., from combustion air source118 and/or line 116) through ports 124 and 125 to the intake valves 141,142, 143 when engine system 100 operates in idle mode. The combustionair is provided at a level that permits smooth idling while the threethrottles 121, 122, 123 are closed.

During operation, while engine system 100 is idling, all three throttles121, 122, 123 are closed and combustion air is fed to intake valves 141,142, 143 through line 137 via ports 124 and 125 (e.g., equalizing portvalves 126 and 127, if used, may be open when the engine system operatesin idle mode and are closed in all other operating conditions—there maybe other alternative utilizations of ports 124 and 125 and the like inoperating conditions other than idle operation in some implementations).In some implementations, when a motor vehicle engine control system 101or the like determines that the engine is no longer operating in idlemode (e.g., based on data collected from the motor vehicle's brake pedal107 and/or accelerator pedal 106), valves 126 and 127 close ports 124and 125, respectively, thus sealing off each combustion cylinder's airintake channel downstream of its respective throttle. When the motorvehicle operator depresses the accelerator pedal 106, throttles 121,122, 123 are opened and pressurized air (e.g., air at approximatelyatmospheric pressure) that has built up on the upstream faces of thethrottle plates of throttles 121, 122, 123 is released to rapidly fillcylinders 151, 152, 153 (e.g., again at approximately atmosphericpressure, a higher charge density than in earlier systems). Because thethrottle-to-intake volume between each throttle mechanism and itsrespective intake valve system is relatively small, cylinders 151, 152,153 hyper-fill (i.e., they fill very rapidly with a higher densitycharge), which substantially improves the engine system's transientresponse (i.e., the time it takes for the engine to respond to a changein throttle position) of engine system 100 as compared to earlierinduction systems. The higher charge density is the result of combustionair filling the cylinders is at approximately atmospheric pressure, thus“packing” more air into each cylinder, and thus increasing the initialpower generated in each cylinder, as well as generating a greater volumeof exhaust gas possessing more harvestable energy than would otherwisebe produced. The larger exhaust gas output of each cylindersubstantially improves the turbocharger response both in terms ofresponse time and pressurization of compressed air delivered for furthercombustion in the cylinders.

Engine power ramp-up in earlier engine systems was negatively affectedby the vacuum created by an intake manifold, namely the pressuredifference between the intake manifold and atmospheric pressure. Morespecifically, in such earlier, naturally aspirated engine systems, apiston moving within a cylinder creates an intake manifold vacuum due toreduced airflow that is choked by a throttle situated at the intakemanifold entrance, restricting airflow through the engine (and thus thepower generated by the engine). Stated another way, this airflowrestriction into the intake manifold results in unused power potentialin a gasoline engine. Mass air flow through an engine determines thatengine's power and can be calculated by multiplying the engine'srotation rate times its displacement and density of inflowing combustionair. Earlier engine systems' constrained combustion air inflow (createdby an upstream vacuum) reduced the combustion air density and thusengine power (and also generated engine drag).

More specifically, in a naturally aspirated engine, the induction volumebetween a traditionally-located throttle body (i.e., upstream of anintake manifold) and the combustion cylinders' intake valves istypically equal to the engine's displacement (i.e., for a 2.0 literengine, the induction volume that must be filled after the throttle isopened is typically approximately 2.0 liters). In turbocharged engines,the induction volume increases substantially (e.g., doubling) due to theaddition of one or more turbocharger compressors, an intercooler and theplumbing required to implement these additional components. Inimplementations of synergistic induction and turbocharging disclosed andclaimed herein, the use of an individual throttle for each cylinderintake port in engine system 100, when transitioning (i.e., ramping up)from idle mode to acceleration mode (i.e., prior to combustion and priorto exhaust gas driving any turbocharger), significantly raises thedensity of the combustion charge entering the cylinders andsignificantly quickens the filling of each combustion cylinder 151, 152,153. In addition to significantly increasing the initial power ramp-upfrom each combustion cylinder, improved induction and cylinder fillingdue to synergistic induction and turbocharging increases exhaust gasvolume to initiate, drive and accelerate turbocharger output.

Thus combustion cylinders 151, 152, 153 each receive a denser chargemore quickly. Once combustion has taken place, exhaust valves 161, 162,163 release exhaust gas into exhaust channels (e.g., exhaust port 171,exhaust port 172, exhaust port 173). Each turbocharger 181, 182, 183 hasa turbine inlet that is affixed in close proximity to its associatedexhaust valve 161, 162, 163 (e.g., so that exhaust gas drivingturbochargers 181, 182, 183 still possess pulse characteristics fromtheir concentrated discharge from the combustion cylinders 151, 152,153). In some implementations the turbine inlet of each turbocharger181, 182, 183 is mounted in a direct line with its associated cylinder'sexhaust valve 161, 162, 163 so that pulse-characteristic-possessingexhaust gas encounters no turns, thus maximizing the exhaust gas energyharvested by turbochargers 181, 182, 183. In some implementationsaffixation of a turbocharger turbine inlet in close proximity to itsassociated exhaust valve can be achieved by mounting a turbochargerdirectly to the exhaust port of a cylinder (e.g., mounting theturbocharger to the cylinder head, possibly using a gasket and bolts, orother suitable mounting means). In some implementations bidirectionalexhaust gas flow balancing passages 188 and optional balancing valves185, 186 (also referred to as “balancing ports”) are used in system 100to permit improved utilization of available turbocharger capacity andexhaust gas energy, to provide more consistent exhaust gas flow (e.g.,constant pressure flow), and to assist in reducing turbulence in thesystem. For example, if turbocharger 181 is unable to utilize exhaustgas discharged from cylinder 151, that “unused” exhaust gas can berouted to the inlet of turbine of turbocharger 182 when balancingpassage 188 and any balancing valve 185 are configured to permit suchcross-flow (similarly, exhaust gas can be shared with turbocharger 183via balancing passage 188 and balance valve 186). The reverse conditionexists with exhaust gas discharged from cylinder 152 and availableturbocharger capacity in turbochargers 181 and 183. Implementations canutilize balancing passages 188 alone, in connection with balancing valve185, in connection with balancing valve 186, or all in combination (andthis exhaust gas flow balancing can be implemented with a 2-cylindersystem and with systems having more than three cylinders). Moreover,optional balancing valves 185, 186 can be configured to permit partialopening of the valves to provide better control of exhaust gascross-flow within system 100. In some implementations balancing valves185, 186 operate in tandem (i.e., both open, both closed, etc.) and canbe controlled by engine control system 101 (e.g., that receives sensorreadings and/or data from the turbochargers 181, 182, 183, thecombustion air source 118 and/or other system components and locations).Based on mapping, programming, testing, etc., cross-flow balancing usingbalancing passages and valves can be programmed and/or available “on thefly” based on changing engine conditions. A wastegate 187 may connectwith cylinder 153 and turbocharger 183 to permit wastegating of exhaustgas that cannot be utilized by any of the turbochargers (e.g., whenbalancing valves are open and intake manifold pressure is too high). Ifwastegate 187 is implemented (e.g., as a “shared” wastegate), exhaustgas can be directed to exhaust line 193. Other combinations ofwastegates and balancing passages and valves can be utilized inconnection with implementations of improved turbocharging, as will beappreciated by those skilled in the art.

By affixing the turbine inlet of each turbocharger in close proximity toits associated cylinder exhaust valve, each turbocharger's area ratio(or area/radius (A/R) ratio) can be substantially increased as comparedto traditional turbocharger A/R ratios (where a single turbocharger isdriven by multiple combustion cylinders and/or receives exhaust gas onlyafter extended, bending travel of the exhaust gas through one or moreexhaust runners).

After driving the turbochargers, exhaust gas is delivered to exhaustsystem 195 via exhaust lines 191, 192, 193 (e.g., to undergo treatmentby a catalytic converter 197 and muffler 199 prior to release to theatmosphere, or for use in an EGR system). Air from air cleaner 176 andmass air flow meter 177 is compressed by the compressors ofturbochargers 181, 182, 183 and delivered via line 114 to intercooler115. In some implementations air from intercooler 115 is delivered vialine 116 to combustion air source 118, which can be an intake manifoldor the like.

Shortly after tip-in as acceleration begins, engine system 100 providesseveral significant improvements over earlier engine systems. First,combustion air can be provided to combustion cylinders 151, 152, 153 atapproximately atmospheric pressure immediately, avoiding the delay dueto induction system filling time and low-density charging. Turbochargingsystem 180 ramps up faster than earlier turbocharging systems due to thehigher-density charging and, in some implementations, due to the closeproximity of turbochargers 181, 182, 183 to the exhaust valves 161, 162,163 of cylinders 151, 152, 153. In some implementations turbochargers181, 182, 183 also are low-inertia turbochargers that provide improvedstart-up performance (e.g., because of smaller turbine wheel andcompressor wheel dimensions and/or lighter-weight materials). Thesefactors (and others in some implementations) generate a bright tip-inresponse from engine system 100 and can eliminate any perceptible turbolag in some implementations. Moreover, because initial filling of thecombustion cylinders uses denser air and charges, initial combustion inthe cylinders generates larger volumes of exhaust gas that likewise getthe turbochargers generating compressed air more quickly.

As the engine accelerates, the combustion air supply system 110continues to provide higher density charges to combustion cylinders 151,152, 153 due to the upper end performance advantages of theturbocharging system 180 delivering compressed air into the combustionair flow to the cylinders. Moreover, notwithstanding the improved tip-inand bright characteristics of the various implementations utilizingimproved induction, turbocharging does not suffer at upper-endperformance due to higher engine power levels. Some earlierturbocharging systems also used smaller inlet nozzles to increase thespeed of exhaust gas impinging on the turbocharger turbines. Thesesmaller-area nozzles would assist at lower engine speeds and/or loads,but create problems (e.g., back pressure) at higher engine loads. Theseproblems and performance limitations due to smaller nozzle areas areavoided using implementations of synergistic induction and turbochargingdescribed and claimed herein.

FIG. 2A illustrates one or more non-limiting examples of combustionassembly 200A that includes a combustion cylinder 251 and variouscomponents, systems, etc. used to operate an internal combustion enginesystem having multiple combustion assemblies implementing synergisticinduction and turbocharging. The engine system in this non-limitingexample contains a number of similar combustion cylinder assemblies andaccompanying cylinders, only one being shown for clarity. A combustionair source 218 provides combustion air to a combustion air intakechannel that may include intake runner 211 and intake port 231. Athrottle mechanism includes a throttle plate 221 operationally affixedwithin the intake channel in close proximity to the intake valve 241 ofcylinder 251 to regulate or otherwise control air flow in intake port231. As noted, the proximity of the throttle 221 to the cylinder intakevalve system (i.e., intake valve 241) can be measured as a linearseparation between the two components, can be measured by volume (e.g.,where the throttle-to-intake volume defined between throttle 221 andintake valve 241 is less than or equal to 80% or 60% of the displacementof cylinder 251), and/or by other means.

A turbine inlet 281A of turbocharger 281 is affixed in close proximityto the exhaust valve 261 of cylinder 251, in some implementations beingmounted directly to a cylinder head or otherwise being mounted to orquite near exhaust port 271. Some engine systems may utilize combustioncylinders having multiple exhaust valves, which all feed exhaust gas toa common exhaust port. Implementations of synergistic induction andturbocharging herein include such configurations. Turbocharger 281 canbe a low inertia turbocharger having lightweight turbine and compressorwheel components, and/or having small dimensions to permit fasterresponse to exhaust gas discharged from cylinder 251 via exhaust valve261 and exhaust port 271. In some implementations a balancing passage288 and optional balancing valve 285 can be connected to exhaust port271 to permit sharing of exhaust gas between and among turbochargersbefore being sent to an exhaust and/or EGR system 291 in an internalcombustion engine system utilizing combustion assembly 200A.Alternatively, valve 285 can be replaced with a wastegate in someimplementations. Balancing passages 288 and valves like valve 285 caninterconnect the turbine inlets of a number of cylinders' turbochargersin a given engine to permit exhaust gas sharing. Air from air cleaner276 and mass air flow meter 277 is compressed by turbocharger 281. Thecompressed air can be sent via line 214 to an intercooler 215, whichsupplied source 218 with compressed air via line 216.

One or more equalizing ports 224 are connected to the air intake channeldownstream of throttle plate 221 and upstream of intake valve 241,permitting a generally even distribution of combustion air to allcylinder intake valves during idle mode operation of engine system 200A.Equalizing ports 224 can interconnect the intake valves of a number ofcylinders in a given engine. Opening and closing of each equalizing port224 can be controlled by a control valve 226 in some implementations. Ascan be seen in FIG. 2A, various cylinder head configurations for aninternal combustion engine system utilizing combustion assembly 200A canbe utilized, as illustrated by alternate cylinder head perimeters 202A,202B and 202C.

If a cylinder head having border 202A is used, then equalizing port(s)224 and throttle plate 221 are outside the cylinder head (e.g., havingthrottle plate 221 mounted within an intake runner 211, or havingthrottle plate 221 mounted between runner 211 and intake port 231, withequalizing port(s) 224 situated downstream of the throttle 221).Throttle plate 221 and equalization port(s) 224 can be integrallymounted using a throttle body assembly or unitary component that hasstructure defining both the throttle plate 221 and each equalizing port224, if desired.

In some implementations equalizing port(s) 224 can be located or definedinside the cylinder head 202B (again, optionally being controlled by avalve 226 or the like). Such a configuration utilizing cylinder head202B can permit mounting of a throttle directly to the cylinder head tofurther enhance its proximity to cylinder intake valve 241 (or, in thecase of multiple intake valves, as shown in FIG. 2B, in close proximityto the multiple intake valves 241A and 241B).

Finally, both the throttle plate 221 and equalizing port(s) 224 can becontained within (e.g., integrated inside) the cylinder head 202C. Thechoice of whether to have equalizing port(s) 224 and/or throttle plate221 inside the cylinder head can be determined on the basis of a numberof factors.

In the exemplary alternate configurations of FIG. 2A, use of anindividual throttle mechanism per cylinder intake port and operationallyaffixing each throttle plate in close proximity to its associated intakevalve system dramatically reduce induction fill time, resulting inhigher combustion charge density supporting higher launch torque underengine acceleration conditions. Stated another way, the combustionassembly 200A, utilizing throttle plate 221 affixed in close proximityto intake valve 241, allows substantially higher density charge fillingof cylinder 251 when an engine transitions from idle mode toacceleration.

In some implementations, in operation, combustion air is provided viaequalizing port(s) 224 during idle mode operation up until idle modeoperation ceases (e.g., when a vehicle engine control system 201determines that the engine is no longer operating in idle mode). Oncethat happens, in anticipation of acceleration, valve(s) 226 can beclosed by engine control system 201 (which can utilize data from variouscomponents such as brake 207 and accelerator pedal 206) in someimplementations. In implementations that do not use valve(s) 226,equalizing ports can be passages that are small enough to effectivelycease functioning as ports once acceleration commences and the pressureof combustion air moving from throttle plate 221 to intake valve 241significantly increases. In either case, when the engine ceases idlemode operation, throttle 221 opens allowing cylinder hyper-filling,immediate filling of cylinder 251 with combustion air at approximatelyatmospheric pressure. This hyper-filling of cylinder 251 producessubstantially higher power in the transition from idle mode to higherengine speed and/or load and also provides a greater exhaust gasdischarge volume to the turbine inlet 281A of turbocharger 281, whichconsequently provides higher pressure compressed air via line 214,through intercooler 215 and line 216 to combustion air source 218. Thiscombination of higher power combustion in cylinder 251 and higher energydriving of turbocharger 281 significantly improves the ramp-up of anengine utilizing combustion assembly 200A implementing synergisticinduction and turbocharging. The sequence noted herein provides nearlyinstantaneous tip-in torque improvement under acceleration conditionsdue to the reduced induction fill time. The effects of high velocity(high inertia) combustion cylinder filling immediately follow frominduction fill time improvement and provide additive torque under launchacceleration conditions.

As noted above, some cylinder configurations utilize a single intakeport that supplies combustion air to a cylinder through multiple intakevalves (Intake Configuration 2). FIG. 2B illustrates a non-limitingexample of this alternate configuration in a combustion assembly 200Bthat is similar to combustion assembly 200A of FIG. 2A, except thatintake port 231 supplies air to cylinder 251 through an intake valvesystem having two intake valves 241A and 241B, instead of a singleintake valve. The operation of assembly 200B is the same as thatdescribed in connection with assembly 200A of FIG. 2A in all otherpertinent aspects. In some engine system operations various operationalpatterns (that is, uniform and/or non-uniform opening and closing) ofmultiple intake valves like 241A and 241B of FIG. 2B might be availableand can be used in connection with implementations of synergisticinduction and turbocharging.

FIG. 3 illustrates further improvements available using implementationsof synergistic induction and turbocharging in a combustion assembly 300in which the combustion cylinder 351 has two intake valves 341A, 341B,each of which receives combustion air through a separate, independentintake port 331A, 331B, respectively. That is, intake port 331A suppliescombustion air to cylinder 351 through intake valve 341A, but notthrough intake valve 341B, and intake port 331B supplies combustion airto cylinder 351 through intake valve 341B, but not through intake valve341A. Combustion air source 318 thus supplies combustion air to cylinder351 via two distinct combustion air intake channels. Intake runners311A, 311B can be used to connect source 318 to intake ports 331A, 331B,respectively. A throttle mechanism includes throttle plate 321A affixedin close proximity to intake valve 341A and throttle plate 321B affixedin close proximity to intake valve 341B. Equalizing ports 324, 325 canbe connected downstream of throttles 321A and 321B and upstream ofintake valve 341A and 341B, again providing a generally evendistribution of combustion air to intake valves 341A and 341B to permitsmooth idling of the engine when throttles 321A and 321B are closed (andto compensate for any irregular throttle leakage when the throttles areclosed). Equalizing ports 324, 325 can interconnect intake ports 311A,311B with other cylinders' intake ports, as shown and the positioning ofthrottle plates 321A, 321B and equalizing ports 324, 325 can be maderelative to alternate cylinder head configurations 302A, 302B, 302C.Equalizing ports 324, 325 can be controlled by valves 326, 327 in someimplementations. Opening and closing of throttles 321A and 321B can beperformed by engine control system 301 using inputs and data fromvarious sources (e.g., accelerator pedal 306 and brake pedal 307, aswell as others).

Beginning combustion using implementations of synergistic induction andturbocharging, the higher volume exhaust gas generated in cylinder 351is used to drive turbocharger 381, which has a turbine inlet 381Aaffixed in close proximity to cylinder exhaust valve 361 (e.g., viaexhaust port 371). Some engine systems may utilize combustion cylindershaving multiple exhaust valves, which all feed exhaust gas to a commonexhaust port. Implementations of synergistic induction and turbochargingherein include such configurations. In some implementations one or morebalancing passages 388 and optional balancing valves 385 caninterconnect exhaust port 371 with one or more additional exhaust portsto permit sharing of exhaust gas between and among turbochargers beforebeing sent to an exhaust and/or EGR system 391 in an internal combustionengine system utilizing combustion assembly 300. Alternatively, valve385 can be replaced with a wastegate in some implementations. Air fromair cleaner 376 and mass air flow meter 377 is compressed byturbocharger 381 and is sent via line 314 to an intercooler 315, andthen on to source 318 via line 316.

The availability of two throttles for cylinder 351 in combustionassembly 300 provides options for various modes of combustion airdelivery to cylinder 351 both at tip-in and at higher engine speedsand/or loads. As noted in connection with FIGS. 4C and 4D, cylindershaving separate, independent intake ports and intake valves can havethrottle mechanisms affixed in close proximity to their respectiveintake valve systems, operating either in unison (that is, all openingand closing together) or in stages or groups comprising subsets ofthrottles that open and close in preselected sequences.

FIG. 4A illustrates one or more implementations of throttle control foran internal combustion engine system implementing synergistic inductionand turbocharging (some components of engine system 400A have beenomitted, however components such as those shown in connection with FIGS.1, 2A and/or 2B may be used). A combustion air source 418 suppliescombustion air to air intake channels (e.g., using intake runners 411,412, 413 and intake ports 431, 432, 433). A single throttle 421, 422,423 controls combustion air flow in each intake channel for cylinders451, 452, 453, respectively. Admission of combustion air from the intakechannels to cylinders 451, 452, 453 is regulated by the opening andclosing a single intake valve 441, 442, 443 in each cylinder 451, 452,453, respectively (cylinders 451, 452, 453 may include multiple intakevalves, examples of which are shown in FIG. 2B and include IntakeConfiguration 2, and the description of the components and operation ofengine system 400A in FIG. 4A may be adapted to such cylinderconfigurations as well). Throttles 421, 422, 423 are affixed in closeproximity to their associated intake valves. A turbocharging system 480is configured to receive exhaust gas from the cylinders 451, 452, 453and in some implementations turbocharging system 480 may include aplurality of turbochargers, each individual turbocharger having aturbine inlet affixed in close proximity to its respective cylinderexhaust valve 461, 462, 463 (e.g., via a respective exhaust port 471,472, 473). Compressed air from turbocharging system 480 is supplied tocombustion air source 418, through intercooler 415 in someimplementations.

Some implementations of engine system 400A may include equalizing ports424 configured to evenly distribute combustion air to cylinders 451,452, 453 when throttles 421, 422, 423 are closed and the engine isoperating in idle mode. In some implementations idle mode combustion airflow can be further controlled using valves 426 in equalizing ports 424.Combustion air may be supplied to equalizing ports 424 by an idle modeair valve 429 or the like, which can act as a throttle bypass solenoid.Throttles 421, 422, 423 and/or equalizing ports 424 can be integral to acylinder head 402 in some implementations.

In implementations illustrated in FIG. 4A, each cylinder's throttlemechanism (including throttles 421, 422, 423) and equalizing port valves426 are controlled by an engine control system 401 (e.g., an ECU).Engine control system 401 receives various inputs and other data fromengine system 400A and a vehicle in which engine system 400A operates.Among these inputs and data include signals from a vehicle acceleratorpedal 406 and a vehicle brake pedal 407. The open/close position of eachthrottle 421, 422, 423 is controlled by a throttle control system thatincludes an individual actuator 444 controlling each throttle 421, 422,423. Actuators 444 can be electrical, electronic, electromechanical,magnetic, mechanical or any other suitable device that can control theopening and closing of throttle plates and/or other throttle mechanismsin an engine system (e.g., an electromechanical device including astepping motor that can change throttle position and being controlled bya control signal or the like, for example from an engine control unit).Generally, many throttle actuators are sensor-based and controllable sothat they can regulate the position and rate of change of a throttleplate being controlled and can provide various types of data to anengine control unit or the like.

In operation, engine system 400A operates in idle mode with all of thethrottles 421, 422, 423 closed and valves 426 open (thus permitting agenerally even distribution of combustion air to cylinder intake valves441, 442, 443 for smooth idling). When the vehicle cease idle modeoperation (e.g., when engine control system 401 determines that idlemode operation has ceased), valves 426 close. In implementations that donot use valves 426 within equalizing ports 424, those equalizing ports424 are proportioned passages that permit the even distribution ofcombustion air during idle mode, but are small enough that higher enginespeed and/or load operation of engine system 400A is unaffected by thepassages. When the vehicle operator then steps on the accelerator pedal406, engine control system 101 signals actuators 444 to open throttles421, 422, 423. Because of the close proximity of the throttle mechanismscomprising throttles 421, 422, 423 to their associated intake valvesystems comprising intake valves 441, 442, 443, opening of throttles421, 422, 423 by actuators 444 provides hyper-filling of cylinders 451,452, 453. The combination of throttles 421, 422, 423 mounted in closeproximity to cylinders 451, 452, 453 and turbocharging system 480provide for synergistic induction and turbocharging that permitsimproved tip-in and faster ramp-up of engine speed, load and/or power.As noted this performance improvement can be further enhanced byutilizing an individual turbocharger for each cylinder combustionassembly, especially when each turbocharger's turbine inlet is affixedin close proximity to its associated cylinder's exhaust valve and/orwhen low-inertia turbochargers are used.

FIG. 4B illustrates one or more implementations of throttle control foran internal combustion engine system 400B implementing synergisticinduction and turbocharging (again, some components of engine system400B have been omitted, however components such as those shown anddiscussed in connection with FIGS. 1, 2A and/or 2B may be used). Theoperation of engine system 400B is similar to that of system 400A ofFIG. 4A, except for implementation of a different throttle controlstructure and operation. Instead of having individual actuators for eachthrottle, engine system 400B utilizes a throttle control systemcomprising a single actuator 445 mounted to throttle 422. As withactuators 444 of FIG. 4A, operation of actuator 445 is controlled byengine control system 401. However, in addition to directly controllingthrottle 422, actuator 445 is mechanically linked to throttles 421 and423 using linkage 446, which is thus operationally connected to therespective throttle plates. This linkage 446 can include springs 447that bias throttles 421, 423 when in their closed positions. Operatingthrottles 421, 422, 423 with a common actuator employing spring biasingthus helps to ensure closure of multiple throttles in system 400B. Thespring bias compensates for variations in the closed positions of thethrottle plates in each throttle mechanism, allowing each to becompletely closed while all are operated by a common actuator. Thisreduces the total throttle leakage, improving operation of a throttlebypass solenoid 429 to achieve and maintain stable idle mode engineoperation (e.g., by maintaining a stable RPM).

FIG. 4C illustrates one or more implementations of throttle control foran internal combustion engine system 400C implementing synergisticinduction and turbocharging (again, as with engine systems 400A and400B, some components may be omitted, however components such as thoseshown and discussed in connection with FIGS. 1, 2A, 2B and 3 may beused). The operation of engine system 400C is similar to that of system400B of FIG. 4B, except that engine system 400C has combustionassemblies comprising cylinders 451, 452, 453 that utilize multipleintake valves 441A, 441B, 442A, 442B, 443A, 443B; more specifically,each combustion cylinder's intake valve system has two intake valves,each of which is individually supplied with combustion air via anindependent intake channel. In the non-limiting example of FIG. 4C thereare a total of six throttles 421A, 421B, 422A, 422B, 423A, 423Bregulating combustion air flow through the intake runners 411A, 411B,412A, 412B, 413A, 413B and intake ports 431A, 431B, 432A, 432B, 433A,433B to cylinders 451, 452, 453. Each cylinder has a throttle mechanismthat includes two throttle plates, each of which controls air flowthrough an individual intake channel connected to a single intake valve.In some implementations of synergistic induction and turbocharging withmultiple-intake-valve cylinders, the throttles may be operated in unison(i.e., all throttles are closed and opened identically). The use of asingle actuator for each throttle can be employed (similar to theimplementation(s) shown in FIG. 4B). FIG. 4C illustrates a throttlecontrol system that includes a common actuator 445 using a mechanicallinkage 446 and biasing springs 447 to link all throttles 421A, 421B,422A, 422B, 423A, 423B and thus produce matched opening and closing ofthose throttles. Again, because each of throttles 421A, 421B, 422A,422B, 423A, 423B is affixed in close proximity to its associated intakevalve 441A, 441B, 442A, 442B, 443A, 443B, the opening of the throttlesby actuator 445 and linkage 446 leads to rapid filling of cylinders 451,452, 453 with dense combustion charges. This hyper-filling of thecombustion cylinders likewise generates more substantial and energeticexhaust gas to drive turbo system 480, which can be a standardturbocharging system or can include a single turbocharger for eachcylinder, wherein each turbocharger includes a turbine inlet affixed inclose proximity to a single exhaust valve 461, 462, 463.

FIG. 4D illustrates one or more implementations of throttle control foran internal combustion engine system 400D implementing synergisticinduction and turbocharging (again, as with engine systems in FIGS.4A-4C, some components may be omitted, however components such as thoseshown and discussed in connection with FIGS. 1, 2A, 2B and 3 may beused). The operation of engine system 400D is similar to that of system400C of FIG. 4C in that cylinders 451, 452, 453 of engine system 400Dutilize multiple intake valves 441A, 441B, 442A, 442B, 443A, 443B; morespecifically, each combustion cylinder's intake valve system has twointake valves, each of which is individually supplied with combustionair via an independent intake channel. In the non-limiting example ofFIG. 4D there are a total of six throttles 421A, 421B, 422A, 422B, 423A,423B regulating combustion air flow through the intake runners 411A,411B, 412A, 412B, 413A, 413B, respectively, and intake ports 431A, 431B,432A, 432B, 433A, 433B, respectively, to cylinders 451, 452, 453,respectively. Each cylinder has a throttle mechanism that includes twothrottle plates, each of which controls air flow through an individualintake channel connected to a single intake valve. In someimplementations of synergistic induction and turbocharging withmultiple-intake-valve cylinders, the set of throttles may be operated insubsets, groups or in a staged manner (i.e., all throttles do not closeand/or open identically).

Implementations of synergistic induction and turbocharging illustratedin FIG. 4D utilize staged opening and/or closing of throttles usingmultiple actuators and linkages that permit opening a subset of theindividual throttles to achieve staged induction. FIG. 4D illustrates athrottle control system that includes a first actuator 445A and itsassociated linkage 446A (including spring biasing 447A) configured tocontrol operation of throttles 421A, 422A, 423A to produce uniformopening and closing of throttles within the first subset. Likewise, asecond actuator 445B and its associated linkage 446B (including springbiasing 447B) are configured to control operation of throttles 421B,422B, 423B to produce uniform opening and closing of throttles withinthe second subset.

Because each cylinder's throttle mechanism (comprising throttle pairs421A/421B, 422A/422B, and 423A/423B) is affixed in close proximity toits associated intake valve system (comprising intake valve pairs441A/441B, 442A/442B, and 443A/443B, respectively), the opening of athrottle by its connected throttle control system actuator and linkageleads to rapid filling of that throttle's cylinder with dense combustioncharges. This hyper-filling of the combustion cylinders likewisegenerates more substantial and energetic exhaust gas to drive turbosystem 480, which can include a single turbocharger having a turbineinlet affixed in close proximity to a single exhaust valve 461, 462,463.

In operation, engine system 400D may operate in idle mode with allthrottle plates 421A, 421B, 422A, 422B, 423A, 423B closed. Combustionair for smooth idle mode operation is fed by valve 429 through thepassages of equalizing ports 424 that interconnect the air intakechannels of the cylinders (e.g., interconnecting the intake ports orinterconnecting the intake runners) at a point downstream of thethrottle plates and upstream of the intake valves. Effectively,equalizing ports 424 interconnect the intake ports of the cylinders(and, as noted in connection with FIGS. 2A, 2B and 3, equalizing ports424 may or may not be integral to cylinder head 402). When idle modeoperation ceases, valves 426 close, thus sealing the air intake channelsof the cylinders 451, 452, 453. In other implementations in which valves426 are not used, the passages of equalizing ports 424 may besufficiently small in diameter that air flow between cylinders' intakechannels is generally inconsequential once acceleration begins.

In some implementations equalizing ports 424 only need to interconnect asingle intake port for each cylinder. In FIGS. 4C and 4D, for example,equalizing ports 424 can also be configured to interconnect intake ports431A, 432A and 433A to provide adequate, generally even distribution ofcombustion air during idle mode operation. This type of configurationavoids the need to interconnect intake ports of the same cylinder, whichcan simplify engine system configuration as well as avoiding anycombustion air leakage between same-cylinder intake ports duringsimultaneous throttle operation (e.g., FIG. 4C) and during stagedthrottle operation (e.g., FIG. 4D). This interconnection of only oneintake port per cylinder would mean that not all of the equalizing portsillustrated in the Figures would be necessary. For example, in FIG. 3,equalizing ports 325 and valve 327 could be eliminated, leaving intakeport 331A connected to only one other intake port for each cylinder incombustion assembly 300.

In some implementations when accelerator pedal 406 is depressed,actuator 445A switches to open and, through linkage 446A, throttles421A, 422A, 423A are opened. Actuator 445B remains in its closedposition, keeping throttles 421B, 422B, 423B closed (via linkage 446Band, in some implementations, spring-biasing from springs 447B thataccommodate variations in throttles' closed positions to reduce oreliminate leakage when closed). Opening only one intake channel for eachcylinder provides advantages over operational modes in which allthrottles for all intake channels are opened in unison. For example,with regard to cylinder 451, when actuator 445A and linkage 446A openthrottle 421A (and throttle 421B remains closed), which has a throttleplate affixed in close proximity to intake valve 441A, the velocity ofcombustion air flowing through intake port 431A and intake valve 441A issubstantially higher than it would be if both throttles 421A, 421Bopened together. The cross-sectional area of only one intake port 431Athus leads to faster combustion air flow and faster filling of cylinder451. Similar rapid filling occurs with regard to throttle 422A andcylinder 452 and with regard to throttle 423A and cylinder 453. Anyminor leakage of combustion air through port 424 connecting intakerunner 411A and intake runner 411B has little or no effect on thehyper-filling of cylinder 451 through intake runner 411A and intake port431A. This staged combustion air flow using a two-actuator-based controlsystem per cylinder delivers more combustion air to the cylinder in adenser charge and thus yields higher power at low RPM.

As the engine system 400D reaches higher speeds, actuator 445B andlinkage 446B can then open the remaining throttles 421B, 422B, 423B toprovide greater combustion air flow to the cylinders. In someimplementations the “A” throttle plates remain open and the cylindersrunning until maximum torque is achieved for single-port operation ofsystem 400D. That is, the cylinders are run with only one port openuntil single-port torque is maximized. When this torque peak is reached,the “B” throttle plates can then be opened to provide dual-port air flowto each cylinder. A cylinder's throttle mechanism in FIG. 4D can beconsidered in close proximity to the cylinder's intake valve system whenthe total intake volume between the throttle mechanism and intake valvesystem is at or below a given threshold in some implementations (e.g.,80% or 60%). Because the throttle-to-intake volume in suchimplementations is defined as the sum of both intake channels' volumesbetween a closed throttle plate and a closed intake valve, spacing ofthe “A” port throttle plate from the “A” port intake valve does not haveto identical to the spacing of the “B” port throttle plate from the “B”port intake valve, so some adjustability is available for positioningeach throttle plate relative to its respective intake valve.

Again, because the turbochargers do not require small nozzles or thelike for low-end performance improvement, operation of engine system400D at higher speeds is more robust than with earlier turbochargersystems that are “overly tuned” to low-end or low-speed performancecompensation. Features such as large A/R ratios can be implemented tofurther improve turbocharger operation in these types of systems.

In various implementations disclosed herein, reference has been made tolow-inertia turbochargers and the like. Such implementations allow useof low rotational inertia turbochargers that have smaller-diameterturbine wheels and compressor wheels than have been used in traditionalturbocharging systems (e.g., turbochargers in which the turbine wheelmeasures less than 3 inches, less than 2.6 inches, or less than 2.1inches; also turbochargers in which the turbine wheel has a diameterless than the combustion cylinders' bore diameter). The reduced size ofsuch turbocharger components dramatically reduces the rotational inertiaof a turbocharger to yield greatly improved tip in performance. Therelative rotational inertia of turbocharger components can be differentfor various types and sizes of engines. In some implementations thedimensions of each turbocharger's turbine wheel includes a diameter thatis less than the bore diameter of the engine's combustion cylinders.This sizing limitation on a turbocharger's turbine wheel in someimplementations takes into account different engine sizes while stillreducing the turbocharger rotational inertia relative to traditionalturbo systems for internal combustion engines. Combinations of thesefeatures permit high performance operation at high RPM and/or loadlevels. They also provide simple, reliable and economical configurationsthat yield greatly improved tip in and operation at low RPM and/or lightload levels as well as improving fuel economy and exhaust emissions.

In some non-limiting examples, the impact of smaller turbochargercomponents on spool up can be seen. In a multiple-cylinder turbochargerof earlier systems (that is, where a single turbocharger receivesexhaust gas from two or more combustion cylinders), if the turbine ofsuch a multiple-cylinder turbocharger has a diameter of 3.25 inches anda rotating mass of 1.1 pounds, the turbine's moment of inertia is(0.5)(m*r²) or 1.452 lb-int. In implementations of synergistic inductionand turbocharging using low-inertia turbochargers, if the turbine ofeach one-cylinder turbocharger has a diameter of 2.50 inches and arotating mass of 0.58 pounds, each turbine's moment of inertia is(0.5)(m*r²) or 0.453 lb-int. In this illustrative example theone-cylinder turbocharger's turbines have a moment of inertia that isless than one third that of the multiple-cylinder turbocharger'sturbine. Implementations of synergistic induction and turbocharging inan internal combustion engine can include turbochargers having turbinediameters of less than 3 inches and, in some implementations, less than2.6 inches and, in yet other implementations, less than 2 inches, thusgreatly reducing the rotational inertia of such turbochargers (whichincludes their compressor wheels and other structure as well) ascompared to larger turbochargers used in earlier multi-cylinder internalcombustion engine systems. In some implementations the turbine wheeldiameter is limited to being less than the bore diameter of the engine'scombustion cylinders. Dimensions for compressor wheels are comparable inmany cases to those for turbine wheels, though compressor wheelmaterials typically differ from turbine wheel materials. Therefore,implementations of synergistic induction and turbocharging in internalcombustion engine systems can include compressor wheels having diametersof less than 3 inches and, in some implementations, less than 2.6 inchesand, in yet other implementations, less than 2 inches, thus furtherreducing the rotational inertia of such turbochargers.

Many engines experience high velocity “ram charging” benefits atmid-range and high power operating conditions, which are significantlyabove initial launch acceleration conditions. “Ram charging” occurs whenthe incoming combustion air continues filling a cylinder even if thepiston is moving past bottom dead center due to the inertia of theincoming combustion air and its compressibility. Air is drawn into acombustion cylinder chamber by piston movement from top dead center tobottom dead center. The intake valve remains open after bottom deadcenter for 50 to 90 crank angle degrees. At low RPM and low fillingvelocity, air flow is reversed in direction and pushed back through theintake valve and out of the cylinder when the piston rises after hittingbottom dead center. However, when filling velocity and air mass inertiaincrease sufficiently, charge filling (i.e., combustion air intake) willcontinue to increase after bottom dead center where reverse air flow isovercome by the air flow's filling velocity and induction runner massair inertia.

When an engine is equipped with two intake valves per cylinder withseparate, independent intake ports for each intake valve and separate,independent intake runners, each of which supports one of the intakevalves, the benefits of “ram charging” can be achieved at low engineRPMs under acceleration conditions if one intake runner is initiallyclosed by a throttle plate, and remains closed until mid-range RPM andtorque is achieved. As noted in connection with FIG. 4D separateoperation of throttle 421A and throttle 421B provides for opening ofonly throttle 421A at tip-in so that high velocity combustion air can besupplied to cylinder 451 via intake valve 441A. Because of this highervelocity using only one intake port, ram charging of combustion air incylinder 451 can be achieved at low RPM and torque levels, acharacteristic not available with earlier induction systems.

FIG. 5 illustrates synergistic induction and turbocharging in aninternal combustion engine system 500 similar to system 100 FIG. 1.However, system 500 uses a generic turbocharging system 580 that maycomprise one or more turbochargers and related components, features andcharacteristics. Some implementations of synergistic induction andturbocharging can utilize one low-inertia turbocharger for eachcylinder, where the turbocharger's turbine inlet is affixed in closeproximity to the cylinder's exhaust valve (e.g., where theexhaust-to-turbine volume is less than 80% of the cylinder displacementor, in some implementations, where the exhaust-to-turbine volume is lessthan 60% of the cylinder displacement). Some implementations ofsynergistic induction and turbocharging can use an earlier type ofturbocharger system in which a single turbocharger receives exhaust gasfrom multiple cylinders through runners or the like. These turbochargingsystems do not have the same response benefits of aone-turbocharger-per-cylinder system, but nevertheless can be part ofsynergistic induction and turbocharging in internal combustion enginesystems. Additionally, system 500 shows an optional exhaust gasrecirculation (EGR) system 585 that can be controlled in part by an EGRthrottle 587 that can control the flow of recirculated exhaust gas intothe combustion air supply.

Mounting a turbocharger in close proximity to the cylinder exhaustvalve(s) may present packaging challenges, depending on the size andconfiguration of the turbochargers utilized, especially with regard tolateral interference. FIG. 6A illustrates one implementation ofsynergistic induction and turbocharging in an internal combustion enginesystem 600A in which the individual turbochargers are nested to permitmounting of each turbocharger in close proximity to the exhaust valve ofits corresponding cylinder, as well as simplifying the plumbing androuting of fresh air and exhaust gas. Turbochargers are mounted to theengine cylinder head or the like using an angular orientation thatfacilitates routing of fresh air and exhaust gas, as well as spacing ofturbochargers relative to one another. This nesting of turbochargers insome implementations provides improved or optimal mounting of theturbochargers so that they are affixed in close proximity to the exhaustvalves of their respective cylinders. In some implementations, anangular orientation of 15° to 75° can be used (the “angular orientation”of each turbocharger being measured between the line connecting thecenters of the cylinder head exhaust ports and the turbocharger shaftaxis, in a plane parallel with the cylinder head exhaust face), thougheach engine's cylinder arrangement, cylinder block configuration andcylinder head configuration may affect the ways in which turbochargerscan be affixed in close proximity to the cylinders' exhaust valve(s).

FIGS. 6A and 6B show an exemplary nesting implementation using anangular orientation (as defined above) of approximately 45° for eachturbocharger (it is possible that all turbochargers in an implementationmight not have the same angular orientation), which provides space forplumbing of compressed air and exhaust gas, as well as adequate spacefor the turbines and compressor wheels of the turbochargers 660, 670,680. Angular orientations that provide suitable access to inlets andoutlets, as well as unobstructed operation of the turbochargers'turbines and compressor wheels may be used in some implementations.

System 600A shows an air cleaner 606 or other source of fresh airprovided to fresh air line 616. Three turbochargers 660, 670, 680 areconnected to line 616. Exemplary turbocharger 660 has an exhaust gasinlet 661 affixed in close proximity to a first cylinder exhaust valve(e.g., by mounting the turbocharger 660 directly to the cylinder headthat partially defines and houses the first cylinder). As noted herein,a turbocharger turbine inlet affixed in close proximity to itsassociated exhaust valve may be operationally mounted or otherwisesituated so that an exhaust-to-turbine volume is less than or equal to80% of the cylinder displacement, where the exhaust-to-turbine volume isdefined as the volume between a closed exhaust valve and theturbocharger's turbine inlet. In some implementations a turbochargerturbine inlet affixed in close proximity to its associated exhaust valvemay be operationally mounted or otherwise situated so that anexhaust-to-turbine volume is less than or equal to 60% of the cylinderdisplacement. In some implementations a turbocharger turbine inletaffixed in close proximity to its associated exhaust valve may beoperationally mounted or otherwise situated so that exhaust gasdischarged from a cylinder still possesses its pulse characteristics asit enters the turbocharger turbine inlet. In some implementations aturbocharger turbine inlet affixed in close proximity to its associatedexhaust valve may be operationally mounted or otherwise situated so thatthe linear distance the exhaust gas travels from exhaust valve to theturbocharger turbine inlet is less than or equal to 10 inches, 8 inches,6 inches, 4 inches or 2 inches.

Exhaust gas turbine inlet 661 is depicted in FIG. 6A as acceptingexhaust gas traveling in a direction perpendicularly out of the plane ofthe drawing in FIG. 6A. Exhaust gas discharged from the first cylinder'sexhaust valve(s) spin turbine 662 and thus shaft 664 and compressorwheel 665. After engaging the turbine 662, the exhaust gas is dischargedfrom turbocharger 660 via turbine outlet 663 and thence to the engine'sexhaust system 690. Fresh air supplied via line 616 to compressor inlet666 is pressurized by compressor wheel 665 and the pressurized fresh airexits turbocharger 660 through compressor outlet 667. In FIG. 6A thecompressed fresh air from each turbocharger 660, 670, 680 can besupplied directly to a combustion air source (not shown), such as anintake manifold. Again, as with the turbine inlet 661, compressor outlet667 is depicted in FIG. 6A as discharging pressurized fresh airtraveling in a direction perpendicularly out of the plane of the drawingin FIG. 6A.

Similarly, turbocharger 670 has a turbine inlet 671 for turbine 672 thataccepts exhaust gas from a second cylinder and drives compressor wheel675 to pressurize fresh air that is then discharged from compressoroutlet 677. Also, a third turbocharger 680 accepts exhaust gas from athird cylinder via turbine inlet 681 and provides pressurized fresh airthrough compressor outlet 687. As noted in connection with someimplementations, exhaust gas from the various cylinders can be madeavailable to multiple turbochargers via balancing passages and balancingvalves or the like (not shown). In FIG. 6A the pressurized fresh air canbe supplied directly to the combustion air source or can be configuredin various ways. One such implementation for configuring pressurizedfresh air from the turbochargers' compressors is illustrated in FIG. 6B.

System 600B of FIG. 6B illustrates optional configuring of compressorfresh air supplying and pressurized fresh air outputs of turbochargers660, 670, 680. The components of system 600B of FIG. 6B operateanalogously to those of system 600A in FIG. 6A. However, the compressoroutlet 667 of turbocharger 660 has a pressurized fresh air supply line668 connected to valve 691, which provides the option of supplyingpressurized fresh air output by turbocharger 660 to the compressor inlet676 of turbocharger 670. Likewise, compressor outlet 677 of turbocharger670 can supply its pressurized fresh air via line 678 through valve 692to the compressor inlet 686 of turbocharger 680. As opposed to “inparallel” compressed air routing (e.g., as shown in FIG. 1), pressurizedfresh air from compressor outlet 687 in system 600B can then be suppliedat a higher pressure to an intake manifold or the like using an “inseries” compressed air routing configuration.

In some implementations of synergistic induction and turbocharging, forexample as shown in FIG. 7, individual combustion air lines 1111, 1112,1113 can be used to supply combustion air directly to intake runners111, 112, 113. While these lines are shown in FIG. 7 as differentlengths (these combustion air supply lines are being depictedschematically), in some implementations the length of each combustionair pathway (e.g., runners or other connecting plumbing) fromintercooler 115 to each throttle 121, 122, 123 is approximately equal toprovide even pressurization prior to opening of the throttle plates.

FIG. 8 illustrates one or more methods for operating an internalcombustion engine system implementing one or more modes of synergisticinduction and turbocharging. The engine system of FIG. 8 has a pluralityof combustion cylinder assemblies, each of which comprises a combustioncylinder having one or more exhaust valves that discharge exhaust gas toan exhaust port and having an intake valve system comprising one or moreintake valves. Combustion air is supplied to each combustion cylinderfrom a combustion air source via a single intake port that delivers thecombustion air to the cylinder through the one or more intake valves(e.g., as in Intake Configurations 1 and 2, above). Each combustionassembly also comprises a throttle that is affixed in close proximity tointake valve system (i.e., the one or more intake valves) and thatcontrols combustion air flow from the combustion air source through thesingle intake port to the one or more intake valves. The variouscombustion assemblies' intake ports are interconnected by one or morevalved equalizing ports that control combustion air flow between theintake ports, including supplying idle mode combustion air to thecombustion cylinder assemblies when the engine operates in idle mode.

FIG. 8 illustrates operating one of the plurality of the combustionassemblies, the illustrated process 800 being repeated by eachcombustion assembly in the engine system in a normal sequencing ofcombustion cylinder ignition. Process (800) begins with the enginesystem operating in idle mode (802), for example when an engine controlsystem (e.g., an ECU) determines that the engine is operating in idlemode. The engine transitions out of idle mode (804) and any equalizingport(s) supplying combustion air to the combustion assembly during idlemode operation are closed. The accelerator pedal is then engaged (806)and the combustion assembly throttle (which is affixed in closeproximity to the intake valve system comprising one or more intakevalves) is opened. The cylinder rapidly fills with combustion air andthe charge is ignited (808). Exhaust gas from the ignition is dischargedthrough an exhaust port and drives a turbocharger having a turbine inletaffixed in close proximity to the cylinder exhaust port (810). If idlemode is not detected (812), the compressed air from the driventurbocharger is supplied to the combustion air source and is used forsubsequent filling of the cylinder (808). If idle mode operation of theengine is detected (812), then the throttle is closed and any equalizingport(s) opened to supply combustion air to the combustion assemblycylinder during idle operation (802).

FIG. 9 illustrates one or more methods for operating an internalcombustion engine system implementing one or more modes of synergisticinduction and turbocharging. The engine system of FIG. 9 has a pluralityof combustion assemblies, each of which comprises a combustion cylinderhaving an exhaust valve that discharges exhaust gas to an exhaust port.Each combustion cylinder also has two intake valves—a first intake valveconnected to a combustion air source via a first intake port, and asecond intake valve connected to a combustion air source via a secondintake port that is separate from and independent of the first intakeport. A first throttle is affixed in close proximity to the first intakevalve and controls combustion air flow from the combustion air source tothe cylinder via the first intake port and first intake valve. A secondthrottle controls combustion air flow from the combustion air source tothe cylinder via the second intake port and second intake valve. Thevarious combustion assemblies' first intake ports are interconnected byone or more valved equalizing ports that control combustion air flowbetween the first intake ports.

FIG. 9 illustrates operating one of the plurality of the combustionassemblies, the illustrated process 900 being repeated by eachcombustion assembly in the engine system in a normal sequencing ofcombustion cylinder ignition. Process (900) begins with the enginesystem operating in idle mode (902), for example when a vehicle enginecontrol system determines the engine is operating in idle mode. Theengine transitions out of idle mode (904) and any equalizing port(s)supplying combustion air to the combustion assembly during idleoperation are closed. The accelerator pedal is then engaged (906) andthe combustion assembly's first throttle (which is part of the throttlemechanism that is affixed in close proximity to the intake valve system)is opened. The cylinder hyper-fills, rapidly filling with combustion airdelivered via the first intake port and first intake valve, and thecharge is ignited (908). Exhaust gas from the ignition is dischargedthrough the exhaust port and drives a turbocharger having a turbineinlet affixed in close proximity to the cylinder's one or more exhaustvalves (910). If a threshold (912) is reached (e.g., a maximum torquelevel for single-intake-valve operation), then the second throttle isopened (if it is closed) and combustion air flows from the combustionair source to the cylinder via the second intake port and second intakevalve (914). If the threshold (912) is not reached, and idle modeoperation does not begin (916), then compressed air from the driventurbocharger is supplied to the combustion air source and is used forsubsequent filling of the cylinder (908). If the threshold is notreached, and idle mode operation commences (916), then any openthrottles are closed (918) and any equalizing port(s) opened to supplycombustion air to the combustion assembly cylinder during idle operation(902). As noted by step (920), there may be other operating conditionsin which one or more equalizing ports are partially or completelyopened.

The included descriptions and figures depict specific embodiments toteach those skilled in the art how to make and use the best mode. Forthe purpose of teaching inventive principles, some conventional aspectshave been simplified or omitted. Those skilled in the art willappreciate variations from these embodiments that fall within the scopeof the invention. Those skilled in the art will also appreciate that thefeatures described above can be combined in various ways to formmultiple embodiments. As a result, the invention is not limited to thespecific embodiments described above, but only by the claims and theirequivalents.

What is claimed is:
 1. An internal combustion engine system comprising:a plurality of combustion cylinder assemblies comprising a firstcombustion cylinder assembly and a second combustion cylinder assembly,wherein each combustion cylinder assembly comprises: a cylinder having acylinder displacement; an intake valve system comprising: a first intakevalve controlling admission of combustion air to the cylinder from afirst intake port; and a second intake valve controlling admission ofcombustion air to the cylinder from a second intake port; an exhaustvalve system comprising one or more exhaust valves controlling dischargeof exhaust gas from the cylinder to one or more exhaust ports; and aninduction system comprising a throttle mechanism comprising: a firstthrottle operationally affixed to control air flow through the firstintake port, wherein the first throttle and the first intake valvedefine a first throttle-to-intake volume in a first intake channel; anda second throttle operationally affixed to control air flow through thesecond intake port, wherein the second throttle and the second intakevalve define a second throttle-to-intake volume in a second intakechannel; wherein the sum of the first throttle-to-intake volume plus thesecond throttle-to-intake volume is not more than 80% of the cylinderdisplacement; and a turbocharger comprising a turbine inlet connected tothe exhaust valve system by an exhaust channel comprising the one ormore cylinder exhaust ports.
 2. The engine system of claim 1 furthercomprising an air flow equalizing system, the air flow equalizing systemcomprising: an internal equalizing passage connecting the first andsecond intake ports of each combustion cylinder assembly downstream oftheir respective throttles; and an external equalizing port connectingthe first or second intake port of the first combustion cylinderassembly downstream of its respective throttle with the first or secondintake port of the second combustion cylinder assembly downstream of itsrespective throttle, wherein the external equalizing port providesgenerally uniform idle mode combustion air flow between the first andsecond combustion cylinder assemblies during idle mode operation,wherein each external equalizing port comprises an external equalizingpassage and an external equalizing port valve controlling air flowthrough the external equalizing passage, further wherein the pluralityof combustion cylinder assemblies comprises the first and secondcombustion cylinder assemblies.
 3. The engine system of claim 2 whereinthe engine system further comprises a throttle control systemcomprising: a mechanical linkage operationally connected to the firstthrottle of the first combustion cylinder assembly throttle mechanismand the first throttle of the second combustion cylinder assemblythrottle mechanism; and a linkage actuator comprising a motor connectedto the mechanical linkage and configured to move the mechanical linkagebetween an open throttle position and a closed throttle position.
 4. Theengine system of claim 3 wherein the mechanical linkage comprises abiasing mounting of the first throttle of the first throttle mechanism.5. The engine system of claim 1 further comprising a balancing portsystem comprising one or more balancing ports, wherein each balancingport connects two turbocharger turbine inlets to permit sharing ofexhaust gas among turbochargers.
 6. The engine system of claim 1 furthercomprising a throttle control system comprising: a first mechanicallinkage operationally connecting a first throttle set; a secondmechanical linkage operationally connecting a second throttle set; afirst linkage actuator connected to the first mechanical linkage andconfigured to move the first mechanical linkage between a first openthrottle position and a first closed throttle position; and a secondlinkage actuator connected to the second mechanical linkage andconfigured to move the second mechanical linkage between a second openthrottle position and a second closed throttle position; wherein thefirst throttle set comprises the first throttle of each combustioncylinder assembly and further wherein the second throttle set comprisesthe second throttle of each combustion cylinder assembly.
 7. The enginesystem of claim 6 further comprising an engine control system configuredto move the first mechanical linkage to the first open throttle positionwhen the engine system transitions from idle mode to acceleration and tomove the second mechanical linkage to the second open throttle positionwhen the engine reaches an operational threshold.
 8. The engine systemof claim 7 wherein the operational threshold is maximum torque forsingle-port operation of the engine system.
 9. An internal combustionengine system comprising: a first cylinder assembly comprising: a firstcylinder having a first cylinder displacement; a first intake valvesystem comprising: a first intake valve controlling admission ofcombustion air to the first cylinder from a first intake port; and asecond intake valve controlling admission of combustion air to the firstcylinder from a second intake port; a first exhaust valve systemcomprising one or more first cylinder exhaust valves controllingdischarge of exhaust gas from the first cylinder to one or more firstcylinder exhaust ports; a first induction system comprising a firstthrottle mechanism affixed in close proximity to the first intake valvesystem, the first throttle mechanism comprising: a first throttleoperationally affixed to control combustion air flow into the firstcylinder through the first intake port, wherein the first throttle andthe first intake valve define a first throttle-to-intake volume in afirst intake channel; and a second throttle operationally affixed tocontrol combustion air flow into the first cylinder through the secondintake port, wherein the second throttle and the second intake valvedefine a second throttle-to-intake volume in a second intake channel;wherein the sum of the first throttle-to-intake volume plus the secondthrottle-to-intake volume is not more than 80% of the first cylinderdisplacement; and a first turbocharger comprising a first turbine inletconnected to the first exhaust valve system by a first exhaust channel;a second cylinder assembly comprising: a second cylinder having a secondcylinder displacement; a second intake valve system comprising: a thirdintake valve controlling admission of combustion air to the secondcylinder from a third intake port; and a fourth intake valve controllingadmission of combustion air to the second cylinder from a fourth intakeport; a second exhaust valve system comprising one or more secondcylinder exhaust valves controlling discharge of exhaust gas from thesecond cylinder to one or more second cylinder exhaust ports; a secondinduction system comprising a second throttle mechanism affixed in closeproximity to the second intake valve system, the second throttlemechanism comprising: a third throttle operationally affixed to controlcombustion air flow into the second cylinder through the third intakeport, wherein the third throttle and the third intake valve define athird throttle-to-intake volume in a third intake channel; and a fourththrottle operationally affixed to control combustion air flow into thesecond cylinder through the fourth intake port, wherein the fourththrottle and the fourth intake valve define a fourth throttle-to-intakevolume in a fourth intake channel; and wherein the sum of the thirdthrottle-to-intake volume plus the fourth throttle-to-intake volume isless than or equal to 80% of the second cylinder displacement; and asecond turbocharger comprising a second turbine inlet connected to thesecond exhaust valve system by a second exhaust channel; an idle airflow equalizing system comprising: a first equalizing passage connectingthe first intake port downstream of the first throttle to the secondintake port downstream of the second throttle; a second equalizingpassage connecting the second intake port downstream of the secondthrottle to the third intake port downstream of the third throttle; athird equalizing passage connecting the third intake port downstream ofthe third throttle to the fourth intake port downstream of the fourththrottle; and a first equalizing port valve configured to control airflow through the second equalizing passage; and an exhaust gas balancingsystem comprising a first balancing passage connecting the first exhaustchannel upstream of the first turbocharger turbine inlet to the secondexhaust channel upstream of the second turbocharger turbine inlet. 10.The engine system of claim 9 further comprising a throttle controlsystem comprising: a mechanical linkage operationally connected to thefirst, second, third and fourth throttles; and a linkage actuatorconnected to the mechanical linkage and configured to move themechanical linkage between an open throttle position and a closedthrottle position.
 11. The engine system of claim 10 wherein themechanical linkage comprises a spring-biasing mounting of at least threeof the first, second, third and fourth throttles.
 12. The engine systemof claim 9 further comprising a throttle control system comprising: afirst mechanical linkage operationally connected to the first and thirdthrottles; a first linkage actuator connected to the first mechanicallinkage and configured to move the first mechanical linkage between afirst open throttle position and a first closed throttle position; asecond mechanical linkage operationally connected to the second andfourth throttles; and a second linkage actuator connected to the secondmechanical linkage and configured to move the second mechanical linkagebetween a second open throttle position and a second closed throttleposition.
 13. The engine system of claim 12 wherein the first mechanicallinkage comprises a first spring-biasing mounting of at least one of thefirst and third throttles, and further wherein the second mechanicallinkage comprises a second spring-biasing mounting of at least one ofthe second and fourth throttles.
 14. The engine system of claim 12further comprising an engine control system configured to move the firstlinkage to the first open throttle position when the engine systemtransitions from idle mode to acceleration and to move the secondlinkage to the second open throttle position when the engine reaches anoperational threshold.
 15. The engine system of claim 14 wherein theoperational threshold is maximum torque for single-port operation of theengine system.
 16. The engine system of claim 9 wherein the firstturbocharger is a low-inertia turbocharger and further wherein thesecond turbocharger is a low-inertia turbocharger.
 17. The engine systemof claim 16 wherein the first cylinder has a first bore diameter andfurther wherein first turbocharger comprises a first turbine wheelhaving a diameter less than the first bore diameter; and further whereinthe second cylinder has a second bore diameter and further whereinsecond turbocharger comprises a second turbine wheel having a diameterless than the second bore diameter.
 18. The engine system of claim 9wherein the idle air flow equalizing system further comprises an idlemode air source connected to at least one of the equalizing passages.19. The engine system of claim 9 further comprising a third cylinderassembly comprising: a third cylinder having a third cylinderdisplacement; a third intake valve system comprising: a fifth intakevalve controlling admission of combustion air to the third cylinder froma fifth intake port; and a sixth intake valve controlling admission ofcombustion air to the third cylinder from a sixth intake port; a thirdexhaust valve system comprising one or more third cylinder exhaustvalves controlling discharge of exhaust gas from the third cylinder toone or more third cylinder exhaust ports; a third induction systemcomprising a third throttle mechanism affixed in close proximity to thethird intake valve system, the third throttle mechanism comprising: afifth throttle operationally affixed to control combustion air flow intothe third cylinder through the fifth intake port, wherein the fifththrottle and the fifth intake valve define a fifth throttle-to-intakevolume in a fifth intake channel; and a sixth throttle operationallyaffixed to control combustion air flow into the third cylinder throughthe sixth intake port, wherein the sixth throttle and the sixth intakevalve define a sixth throttle-to-intake volume in a sixth intakechannel; and wherein the sum of the fifth throttle-to-intake volume plusthe sixth throttle-to-intake volume is less than or equal to 80% of thethird cylinder displacement; and a third turbocharger comprising a thirdturbine inlet connected to the third exhaust valve system by a thirdexhaust channel; wherein the idle air flow equalizing system furthercomprises: a fourth equalizing passage connecting the fourth intake portdownstream of the fourth throttle to the fifth intake port downstream ofthe fifth throttle; and a fifth equalizing passage connecting the fifthintake port downstream of the fifth throttle to the sixth intake portdownstream of the sixth throttle; and further wherein the exhaust gasbalancing port system comprises a second balancing passage connectingthe second exhaust channel upstream of the second turbocharger turbineinlet to the third exhaust channel upstream of the third turbochargerturbine inlet.
 20. An internal combustion engine system comprising aplurality of one-turbocharger-per-cylinder cylinder assemblies, theengine system comprising: a first cylinder assembly comprising: a firstcylinder having a first cylinder displacement; a first intake valvesystem comprising: a first intake valve controlling admission ofcombustion air to the first cylinder from a first intake port; and asecond intake valve controlling admission of combustion air to the firstcylinder from a second intake port; a first exhaust valve systemcomprising one or more first cylinder exhaust valves controllingdischarge of exhaust gas from the first cylinder to one or more firstcylinder exhaust ports; a first induction system comprising a firstthrottle mechanism affixed in close proximity to the first intake valvesystem, the first throttle mechanism comprising: a first throttleoperationally affixed to control combustion air flow into the firstcylinder through the first intake port, wherein the first throttle andthe first intake valve define a first throttle-to-intake volume in afirst intake channel; and a second throttle operationally affixed tocontrol combustion air flow into the first cylinder through the secondintake port, wherein the second throttle and the second intake valvedefine a second throttle-to-intake volume in a second intake channel;wherein the sum of the first throttle-to-intake volume plus the secondthrottle-to-intake volume is not more than 80% of the first cylinderdisplacement; and a first turbocharger comprising a first turbine inletconnected to the first exhaust valve system by a first exhaust channel;a second cylinder assembly comprising: a second cylinder having a secondcylinder displacement; a second intake valve system comprising: a thirdintake valve controlling admission of combustion air to the secondcylinder from a third intake port; and a fourth intake valve controllingadmission of combustion air to the second cylinder from a fourth intakeport; a second exhaust valve system comprising one or more secondcylinder exhaust valves controlling discharge of exhaust gas from thesecond cylinder to one or more second cylinder exhaust ports; a secondinduction system comprising a second throttle mechanism affixed in closeproximity to the second intake valve system, the second throttlemechanism comprising: a third throttle operationally affixed to controlcombustion air flow into the second cylinder through the third intakeport, wherein the third throttle and the third intake valve define athird throttle-to-intake volume in a third intake channel; and a fourththrottle operationally affixed to control combustion air flow into thesecond cylinder through the fourth intake port, wherein the fourththrottle and the fourth intake valve define a fourth throttle-to-intakevolume in a fourth intake channel; and wherein the sum of the thirdthrottle-to-intake volume plus the fourth throttle-to-intake volume isless than or equal to 80% of the second cylinder displacement; and asecond turbocharger comprising a second turbine inlet connected to thesecond exhaust valve system by a second exhaust channel; a thirdcylinder assembly comprising: a third cylinder having a third cylinderdisplacement; a third intake valve system comprising: a fifth intakevalve controlling admission of combustion air to the third cylinder froma fifth intake port; and a sixth intake valve controlling admission ofcombustion air to the third cylinder from a sixth intake port; a thirdexhaust valve system comprising one or more third cylinder exhaustvalves controlling discharge of exhaust gas from the third cylinder toone or more third cylinder exhaust ports; a third induction systemcomprising a third throttle mechanism affixed in close proximity to thethird intake valve system, the third throttle mechanism comprising: afifth throttle operationally affixed to control combustion air flow intothe third cylinder through the fifth intake port, wherein the fifththrottle and the fifth intake valve define a fifth throttle-to-intakevolume in a fifth intake channel; and a sixth throttle operationallyaffixed to control combustion air flow into the third cylinder throughthe sixth intake port, wherein the sixth throttle and the sixth intakevalve define a sixth throttle-to-intake volume in a sixth intakechannel; and wherein the sum of the fifth throttle-to-intake volume plusthe sixth throttle-to-intake volume is less than or equal to 80% of thethird cylinder displacement; and a third turbocharger comprising a thirdturbine inlet connected to the third exhaust valve system by a thirdexhaust channel; an idle air flow equalizing system comprising: a firstequalizing passage connecting the first intake port downstream of thefirst throttle to the second intake port downstream of the secondthrottle; a second equalizing passage connecting the second intake portdownstream of the second throttle to the third intake port downstream ofthe third throttle; a third equalizing passage connecting the thirdintake port downstream of the third throttle to the fourth intake portdownstream of the fourth throttle; a fourth equalizing passageconnecting the fourth intake port downstream of the fourth throttle tothe fifth intake port downstream of the fifth throttle; a fifthequalizing passage connecting the fifth intake port downstream of thefifth throttle to the sixth intake port downstream of the sixththrottle; and a first equalizing port valve configured to control airflow through the second equalizing passage; and a second equalizing portvalve configured to control air flow through the fourth equalizingpassage; and an exhaust gas balancing system comprising: a firstbalancing passage connecting the first exhaust channel upstream of thefirst turbocharger turbine inlet to the second exhaust channel upstreamof the second turbocharger turbine inlet; a second balancing passageconnecting the second exhaust port upstream of the second turbochargerturbine inlet to the third exhaust channel upstream of the thirdturbocharger turbine inlet; and a throttle control system comprising: afirst linkage operationally connected to the first, third and fifththrottles; a first actuator configured to move the first linkage betweena first open throttle position and a first closed throttle position; asecond linkage operationally connected to the second, fifth and sixththrottles; a second actuator configured to move the second linkagebetween a second open throttle position and a second closed throttleposition; an engine control system configured to move the first linkageto the first open throttle position when the engine system transitionsfrom idle mode to acceleration and to move the second linkage to thesecond open throttle position when the engine reaches an operationalthreshold.